fossil

Crinoid Stem Fossil

Class Crinoidea (Echinodermata)

Hardness: 3 (Calcite); Color: Gray, tan, or white; Luster: Dull to earthy; Shape: Cylindrical or disc-like sections; Structure: Crystalline calcite replaces the original skeleton, often showing a central hole (lumen).

Hardness: 3 (Calcite)
Color: Gray, tan, or white
Luster: Dull to earthy

Identified July 21, 2026More fossil →

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Physical properties

Formation & geological history

Formed from the mineralized remains of marine animals related to starfish. These animals lived in shallow seas from the Ordovician to the present, though most common fossils date from the Mississippian subperiod (358-323 million years ago).

Uses & applications

Used primarily as educational specimens, collectibles, and occasionally in jewelry (beads) or as decorative architectural stone when embedded in limestone.

Geological facts

Crinoids are often called "sea lilies" because of their plant-like appearance, but they are actually animals. In the UK, individual stem segments are sometimes known as "St. Cuthbert's beads."

Field identification & locations

Look for segmented, stackable discs or cylinders in limestone outcrops. They are common in stream beds and road cuts throughout the Midwestern United States and the United Kingdom.